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UC Berkeley alumna Sally Floyd, a computer scientist known for her work on congestion control, died Aug. 25 at age 69, leaving behind her wife Carole Leita — as first reported by the New York Times.

After receiving her bachelor’s degree from UC Berkeley, Floyd received a certificate in electronics from Merritt College, according to her biography on the International Computer Science Institute, or ICSI, Center for Internet Research website. She then worked for eight years at BART, serving as a computer systems engineer. She went on to receive a master’s and PhD from UC Berkeley.

After completing her doctorate in 1989, she spent nine years working in the Network Research Group at the Lawrence Berkeley National Laboratory. In February 1999, she joined the ICSI. She retired in 2009, two years after she was diagnosed with multiple sclerosis.

Floyd was best known for her work on congestion control, which comes into effect when one computer sends a message to another computer and divides the message into packets. Its router then transmits these packets. The speed at which these packets are sent is important because it keeps the networks from getting clogged.

Floyd also co-published a paper on Random Early Detection, or RED, which can detect incoming packets through computing average queue size. If congestion is determined to be in the system, it will notify the connection and preemptively drop the packets using models. This led to the establishment of active queue management.

Eddie Kohler, a professor of computer science at Harvard University, worked with Floyd at ICSI. They believe her focus on congestion control was important, but they also spoke of her with affection.

“She knew herself so well, down to bedrock. She was filled with love,” Kohler said. “She loved her backyard, her wife, her life. It was hard to spend time with her and not come out of it happier.”

Vern Paxson — a campus electrical engineering and computer sciences, or EECS, professor and the leader of the Networking and Security Group at ICSI—echoed these sentiments and said she had a positive impact on his life. Having worked with Floyd several times, he referred to her as a mentor and pointed to Floyd’s ability to engage with people and help them.

In a Facebook post, Mark Allman, a senior researcher in the Networking and Security Group at the ICSI and adjunct faculty in EECS at Case Western Reserve University, described an interaction he observed where Floyd sat on a hotel floor and talked to a graduate student she had just met.

“She is one of those folks I feel like I owe a debt that I cannot re-pay,” Allman said in the post.